Assessment of Layer Thickness and Interface Quality in CoP Electrodeposited Multilayers

Area of Science:

• Materials Science
• Physics
• Electrochemistry

Background:

• Cobalt-phosphorus (CoP) alloys exhibit tunable magnetic properties through multilayered structures.
• Amorphous nature of CoP presents challenges in characterizing interfacial quality, crucial for optimizing soft magnetic properties.

Purpose of the Study:

• To investigate the impact of layer thickness on the interfacial quality and magnetic properties of electrodeposited CoP amorphous multilayers.
• To establish the critical layer thickness for maintaining distinct layers and controlling magnetic anisotropy.

Main Methods:

• Electrodeposition using pulse plating to create CoP multilayers with varying phosphorus content.
• Rutherford backscattering spectroscopy (RBS) to analyze layer composition and interfacial roughness.
• Magnetostriction measurements to determine magnetic anisotropy and layer thickness limitations.

Main Results:

• Electrodeposited CoP/CoP amorphous multilayers with layers down to 20 nm exhibit well-defined layers and interfacial roughness below 3 nm.
• A critical layer thickness of 4 nm was identified; below this, layers mix, altering magnetic behavior.
• Layer mixing below 4 nm transitions magnetic anisotropy from in-plane to out-of-plane.

Conclusions:

• The study defines the operational range for controlling magnetic properties of CoP alloys via multilayer structuring.
• Precise control over magnetic anisotropy is achievable by maintaining layer thicknesses above 4 nm.
• RBS and magnetostriction measurements are effective tools for characterizing these amorphous multilayer systems.